Association Between PS-OCT Derived Polarimetric Entropy and RPE Cellular Metrics Measured With Adaptive Optics...

The purpose of this study was to investigate the association between entropy values derived from the retinal pigment epithelium (RPE) layer using polarization-sensitive optical coherence tomography (PS-OCT) and RPE cellular metrics obtained by adaptive optics transscleral flood illumination (AO-TFI), including cell density, spacing, regularity, and dispersion. We further aimed to determine which cellular structural alterations in retinitis pigmentosa (RP) are reflected by entropy.

Healthy controls and patients with RP who underwent both PS-OCT and AO-TFI imaging were included. Spearman correlation coefficients were calculated to assess the relationships between polarimetric entropy in PS-OCT and each AO-TFI-derived parameter. To account for repeated measurements within the same eye and the effects of group and eccentricity, linear mixed-effects models were constructed to evaluate the independent associations between entropy and AO-TFI metrics after adjustment for these factors.

Polarimetric entropy showed the strongest positive correlation with RPE cell density among the AO-TFI parameters and was negatively correlated with spacing of RPE cells. No clear associations were observed with regularity or dispersion. In linear mixed-effects models, the association between entropy and RPE cell density differed between groups, with a significant association observed in the RP group but not in healthy controls.

PS-OCT-derived polarimetric entropy was associated with RPE cell density measured by AO-TFI, with the association primarily observed in RP rather than in healthy controls. These findings suggest that correspondence between the two imaging modalities may contribute to quantitative assessment of outer retinal-RPE complex alterations and has potential utility as a biomarker in retinal degenerative diseases.